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THE EARTH'S CRUST 



older mountains of the earth are all comparatively low, not 

 necessarily because they were never elevated as high as the 

 lofty mountains of to-day, but because their greater age has 

 longer subjected them to erosion and thus reduced their 

 height. 



The central part of lofty mountains is composed of igne- 

 ous rocks, but on the sides overlying these, sedimentary 

 rocks are found. The Rockies, the Alps, and the Himalaya 

 Mountains are of this kind. 



THE MATTE RHORN 

 A famous peak in the Alps. 



Mountain Peaks. In mountain regions the features 

 which are often most impressive are the serrated peaks 

 which rise above the main mass of the mountains. The 

 shapes of these peaks vary greatly in different mountain 



